51st Cracow School of Theoretical Physics
The Soft Side of the LHC
Min-Bias and the Underlying Event at the LHC
Rick Field
University of Florida
Lecture 2: Outline
 How are “min-bias” collisions related to the
“underlying event”.
Zakopane, Poland, June 11-19, 2011
 How well did we do at predicting the behavior of “minbias” collisions at the LHC (900 GeV and 7 TeV)?
CMS
“Minimum Bias” Collisions
 Baryon and Strange Particle Production at the LHC:
Proton
Fragmentation
tuning.
K
Kshort
u s
d s +d s
+
Proton
p

uud
Proton
 
Outgoing Parton
PT(hard)
dss
Initial-State Radiation
ud s
Underlying Event
Proton
Underlying Event
-
K
u s
Outgoing Parton
ATLAS
Final-State
Radiation
UE&MB@CMS
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 1
Toward an Understanding of
Hadron-Hadron Collisions
From Feynman-Field to the LHC
Rick Field
University of Florida
Lecture 3: Tomorrow Evening
 Before Feynman-Field Phenomenology:
Feynman
The Berkeley years.
 The early days of Feynman-Field
Phenomenology.
 From 7 GeV/c p0’s to 1 TeV Jets!
Field
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 2
Proton-Proton Collisions
Elastic Scattering
Single Diffraction
Double Diffraction
M2
M
M1
stot = sEL +sSD
IN +sDD +sHC
ND
“Inelastic Non-Diffractive Component”
Hard Core
The “hard core” component
contains both “hard” and
“soft” collisions.
“Hard” Hard Core (hard scattering)
Outgoing Parton
“Soft” Hard Core (no hard scattering)
Proton
PT(hard)
Proton
Proton
Proton
Underlying Event
Underlying Event
Initial-State
Radiation
Final-State
Radiation
Outgoing Parton
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 3
The Inelastic Non-Diffractive
Cross-Section
Occasionally one of
the parton-parton
collisions is hard
(pT > ≈2 GeV/c)
Proton
Proton
Majority of “minbias” events!
Proton
“Semi-hard” partonparton collision
(pT < ≈2 GeV/c)
Proton
+
Proton
+
Proton
Proton
Proton
+
Proton
Proton
+…
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Multiple-parton
interactions (MPI)!
Page 4
The “Underlying Event”
Select inelastic non-diffractive events
that contain a hard scattering
Proton
Hard parton-parton
collisions is hard
(pT > ≈2 GeV/c)
Proton
1/(pT)4→ 1/(pT2+pT02)2
The “underlying-event” (UE)!
Proton
Given that you have one hard
scattering it is more probable to
have MPI! Hence, the UE has
more activity than “min-bias”.
Cracow School of Physics
Zakopane, June 13, 2011
Proton
+
+
Proton
Proton
Rick Field – Florida/CDF/CMS
“Semi-hard” partonparton collision
(pT < ≈2 GeV/c)
Proton
Proton
+…
Multiple-parton
interactions (MPI)!
Page 5
Allow leading hard
scattering to go to
zero pT with same
cut-off as the MPI!
Model of sND
Proton
Proton
Proton
Proton
Proton
+
Proton
“Semi-hard” partonparton collision
(pT < ≈2 GeV/c)
1/(pT)4→ 1/(pT2+pT02)2
Model of the inelastic nondiffractive cross section!
+
Proton
Proton
Proton
+
Proton
Proton
+…
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Multiple-parton
interactions (MPI)!
Page 6
UE Tunes
Allow primary hard-scattering to
go to pT = 0 with same cut-off!
“Underlying Event”
Fit the “underlying
event” in a hard
scattering process.
Proton
Proton
All of Rick’s tunes (except X2):
1/(pT)4→ 1/(pT2+pT02)2
A, AW, AWT,DW, DWT,
D6, D6T, CW, X1,
“Min-Bias”
“Min-Bias” (add
(ND)single & double diffraction)
and Tune Z1,
are UE tunes!
Proton
Predict MB (ND)!
Proton
+
+
Proton
Proton
Proton
Single Diffraction
Predict MB (IN)!
Cracow School of Physics
Zakopane, June 13, 2011
+…
Proton
+
Proton
Proton
Double Diffraction
M2
M
Rick Field – Florida/CDF/CMS
M1
Page 7
Charged Particle Multiplicity
Charged Multiplicity Distribution
Charged Multiplicity Distribution
1.0E+00
1.0E+00
CDF Run 2 Preliminary
1.0E-01
CDF Run 2 <Nchg>=4.5
CDF Run 2 <Nchg>=4.5
1.0E-02
Probability
Probability
1.0E-02
CDF Run 2 Preliminary
1.0E-01
1.0E-03
1.0E-04
1.0E-05
py Tune A <Nchg> = 4.3
pyAnoMPI <Nchg> = 2.6
1.0E-03
1.0E-04
1.0E-05
1.0E-06
1.0E-06
Min-Bias 1.96
1.0E-07
Min-Bias 1.96
1.0E-07
Charged Particles (|h|<1.0, PT>0.4 GeV/c)
Normalized to 1
Normalized to 1
Charged Particles (|h|<1.0, PT>0.4 GeV/c)
1.0E-08
1.0E-08
0
5
10
15
20
25
30
35
40
45
50
55
0
5
10
Number of Charged Particles
i
20
25
30
35
40
45
50
Number of Charged Particles
“Minimum Bias” Collisions
Proton
15
No MPI!
Tune A!
AntiProton
 Data at 1.96 TeV on the charged particle multiplicity (pT > 0.4 GeV/c, |h| < 1) for “min-bias”
collisions at CDF Run 2 (non-diffractive cross-section).
 The data are compared with PYTHIA Tune A and Tune A without multiple parton
interactions (pyAnoMPI).
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 8
55
PYTHIA Tune A Min-Bias
“Soft” + ”Hard”
Charged Particle Density
1.0E+00
Pythia 6.206 Set A
CDF Min-Bias Data
Charged Density dN/dhdfdPT (1/GeV/c)
1.0E-01
Ten decades!
1.8 TeV |h|<1
1.0E-02
12% of “Min-Bias” events
have PT(hard) > 5 GeV/c!
PT(hard) > 0 GeV/c
1.0E-03
1% of “Min-Bias” events
have PT(hard) > 10 GeV/c!
1.0E-04
1.0E-05
CDF Preliminary
1.0E-06
0
2
4
6
8
PT(charged) (GeV/c)
10
12
14
Lots of “hard” scattering in
“Min-Bias” at the Tevatron!
 Comparison of PYTHIA Tune A with the pT distribution of charged particles for “min-bias”
collisions at CDF Run 1 (non-diffractive cross-section).
pT = 50 GeV/c!
 PYTHIA Tune A predicts that 12% of all “Min-Bias” events are a result of a hard 2-to-2
parton-parton scattering with PT(hard) > 5 GeV/c (1% with PT(hard) > 10 GeV/c)!
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 9
MB Tunes
“Underlying Event”
Predict the “underlying
event” in a hard
scattering process!
Proton
Proton
Most of Peter Skand’s tunes:
S320 Perugia
0, S325 Perugia X,
“Min-Bias”
(ND)
S326 Perugia 6
are MB tunes!
Proton
Fit MB (ND).
Proton
+
Proton
+
Proton
Proton
Proton
+
Proton
Proton
+…
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 10
MB+UE Tunes
“Underlying Event”
Fit the “underlying
event” in a hard
scattering process!
Proton
Proton
Most of Hendrik’s “Professor”
tunes: ProQ20, P329
are MB+UE!
Simultaneous fit
to both MB & UE
“Min-Bias” (ND)
Proton
Fit MB (ND).
Proton
+
Proton
+…
Cracow School of Physics
Zakopane, June 13, 2011
+
Proton
Proton
Proton
+
Proton
Proton
The ATLAS AMBT1 Tune is an MB+UE tune, but
because they include in the fit the ATLAS UE data
with PTmax > 10 GeV/c (big errors) the LHC UE data
does not have much pull (hence mostly an MB tune!).
Rick Field – Florida/CDF/CMS
Page 11
LHC MB Predictions: 900 GeV
Charged Particle Density: dN/dh
Charged Particle Density: dN/dh
5
5
RDF Preliminary
Charged Particle Density
Charged Particle Density
RDF Preliminary
4
3
2
ALICE INEL
Off by 11%!
UA5 INEL
INEL = HC+DD+SD
900 GeV
1
5
-1.5
-1.0
-0.5
0.0
4
Charged Particle Density
-2.0
2
UA5
ALICE
1
pyDW_10mm (3.04)
pyS320_10mm (3.09)
pyS320 INEL (2.70)
0
-2.5
3
NSD = HC+DD
Charged Particle Density: dN/dh
900 GeV
pyDW INEL (2.67)
Charged Particles (all pT)
-3.0
4
RDF Preliminary
0.5
1.0
1.5
0
2.0
2.5
3.0
-3.0
-2.5
-2.0 times
-1.5 1.11
-1.0
3
0.5
1.0
1.5
2.0
2.5
“Minimum Bias” Collisions
“Minimum Bias” Collisions
2
Proton
1
0.0
PseudoRapidity h
PseudoRapidity h
Proton
-0.5
INEL = HC+DD+SD
900 GeV
Charged Particles (all pT)
Proton
ALICE INEL
UA5 INEL
pyDW times 1.11 (2.97)
pyS320 times 1.11 (3.00)
Proton
0
-3.0 ALICE
-2.5 -2.0 -1.5
-1.0 with
-0.5 0.0
0.5
1.0
1.5
2.0 DW
2.5
3.0and Tune S320
 Compares the 900 GeV
data
PYTHIA
Tune
PseudoRapidity
h
Perugia 0. Tune DW uses the old Q2-ordered parton shower and the old MPI
model. Tune S320 uses the new pT-ordered parton shower and the new MPI model.
The numbers in parentheses are the average value of dN/dh for the region |h| <
0.6.
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 12
3.0
ATLAS INEL dN/dh
 None of the tunes fit the
ATLAS INEL dN/dh
data with PT > 100
MeV! They all predict
too few particles.
Off by 20-50%!
 The ATLAS Tune
AMBT1 was designed to
fit the inelastic data for
Nchg ≥ 6 with pT > 0.5
GeV/c!
Cracow School of Physics
Zakopane, June 13, 2011
Soft particles!
Rick Field – Florida/CDF/CMS
Page 13
CMS dN/dh
Charged Particle Density: dN/dh
8
CMS
Charged Particle Density
7 TeV
6
4
RDF Preliminary
2
Tune DW
CMS NSD data
pyDW generator level
All pT
dashed = ND solid = NSD
0
-3.0
-2.5
-2.0
-1.5
-1.0
Soft particles!
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
PseudoRapidity h
 Generator level dN/dh (all pT). Shows the NSD = HC + DD and the HC = ND
contributions for Tune DW. Also shows the CMS NSD data.
“Minimum Bias” Collisions
Proton
Cracow School of Physics
Zakopane, June 13, 2011
Off by 50%!
Rick Field – Florida/CDF/CMS
Proton
Page 14
PYTHIA Tune DW
If one increases the pT
the agreement
improves!
Charged Particle Density: dN/dh
5
Charged Particle Density
RDF Preliminary
4
At Least 1 Charged Particle |h| < 0.8
900 GeV
ALICE INEL data
pyDW generator level
pT > 0.15 GeV/c
Tune DW
3
pT > 0.5 GeV/c
2
pT > 1.0 GeV/c
1
0
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
PseudoRapidity h
 ALICE inelastic data at 900 GeV on the dN/dh distribution for charged particles (pT >
PTmin) for events with at least one charged particle with pT > PTmin and |h| < 0.8 for
PTmin = 0.15 GeV/c, 0.5 GeV/c, and 1.0 GeV/c compared with PYTHIA Tune DW at the
generator level.
“Minimum Bias” Collisions
ProtonThe
same thing occurs at 7 TeV!
Proton
ALICE, ATLAS, and CMS data coming soon.
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 15
PYTHIA Tune DW
Diffraction
contributes less at
harder scales!
Charged Particle Density: dN/dh
5
Charged Particle Density
RDF Preliminary
4
At Least 1 Charged Particle |h| < 0.8
900 GeV
ALICE INEL data
pyDW generator level
pT > 0.15 GeV/c
3
Tune DW
pT > 0.5 GeV/c
2
pT > 1.0 GeV/c
1
dashed = ND solid = INEL
0
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
PseudoRapidity h
 ALICE inelastic data at 900 GeV on the dN/dh distribution for charged particles (pT >
PTmin) for events with at least one charged particle with pT > PTmin and |h| < 0.8 for
PTmin = 0.15 GeV/c, 0.5 GeV/c, and 1.0 GeV/c compared with PYTHIA Tune Z1 at the
generator level (dashed = ND, solid = INEL).
“Minimum Bias” Collisions
Proton
Cannot
trust PYTHIA 6.2 modeling of diffraction!
Proton
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 16
Min-Bias Collisions
Charged Particle Density: dN/dh
Charged Particle Density: dN/dh
6
CMS Data
ALICE Data
PYTHIA Tune Z1
PYTHIA Tune Z1
Charged Particle Density
Charged Particle Density
8
6
NSD = ND + DD
4
Tune Z1
CMS
2
pyZ1 ND = dashed
pyZ1 NSD = solid
7 TeV
NSD (all pT)
4
2
Tune Z1
INEL (all pT)
0
ALICE
INEL = NSD + SD
pyZ1 NSD = dashed
pyZ1 INEL = solid
900 GeV
0
-4
-3
-2
-1
0
1
2
3
4
-4
-3
Pseudo-Rapidity h
-2
-1
0
1
2
3
Pseudo-Rapidity h
 CMS NSD data on the charged particle
rapidity distribution at 7 TeV compared
with PYTHIA Tune Z1. The plot shows the
average number of particles per NSD
collision per unit h, (1/NNSD) dN/dh.
 ALICE NSD data on the charged particle
rapidity distribution at 900 GeV compared
with PYTHIA Tune Z1. The plot shows the
average number of particles per INEL
collision per unit h, (1/NINEL) dN/dh.
“Minimum Bias” Collisions
Okay not perfect, but remember
Proton
we know that SD and DD are not modeled well!
Proton
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 17
4
PYTHIA Tune Z1
Charged Particle Density: dN/dh
5
Charged Particle Density
RDF Preliminary
4
ALICE INEL data
pyZ1 generator level
At Least 1 Charged Particle |h| < 0.8
900 GeV
pT > 0.15 GeV/c
3
pT > 0.5 GeV/c
2
pT > 1.0 GeV/c
1
0
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
PseudoRapidity h
 ALICE inelastic data at 900 GeV on the dN/dh distribution for charged particles (pT >
PTmin) for events with at least one charged particle with pT > PTmin and |h| < 0.8 for
PTmin = 0.15 GeV/c, 0.5 GeV/c, and 1.0 GeV/c compared with PYTHIA Tune Z1 at the
generator level.
“Minumum Bias” Collisions
Okay
not perfect, but remember
Proton
Proton
we do not know if the SD & DD are correct!
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 18
NSD Multiplicity Distribution
Charged Multiplicity Distribution
1.0E-01
RDF Preliminary
data CMS NSD
pyZ1 generator level
Difficult to produce
enough events with
large multiplicity!
CMS
Probability
1.0E-02
7 TeV
900 GeV
1.0E-03
Charged Particles
(all PT, |h|<2.0)
Tune Z1
1.0E-04
0
20
40
60
80
100
Number of Charged Particles
 Generator level charged multiplicity distribution (all pT, |h| < 2) at 900 GeV and 7
TeV. Shows the NSD = HC + DD prediction for Tune Z1. Also shows the CMS
NSD data.
“Minumum Bias” Collisions
Proton
Cracow School of Physics
Zakopane, June 13, 2011
Okay not perfect!
But not that bad!
Rick Field – Florida/CDF/CMS
Proton
Page 19
MB versus UE
Divide be 2p
Charged Particle Density: dN/dhdf
Charged Particle Density: dN/dh
2.5
CMS Data
CMS Data
PYTHIA Tune Z1
PYTHIA Tune Z1
Charged Particle Density
Charged Particle Density
8
6
NSD = ND + DD
4
Tune Z1
CMS
2
pyZ1 ND = dashed
pyZ1 NSD = solid
7 TeV
NSD (all pT)
2.0
1.5
1.0
0.5
pyZ1 ND = dashed
7 TeV
NSD (all pT)
pyZ1 NSD = solid
0.0
0
-4
-3
-2
-1
0
1
2
3
4
-4
-3
-2
-1
0
1
2
3
Pseudo-Rapidity h
Pseudo-Rapidity h
 CMS NSD data on the charged particle
rapidity distribution at 7 TeV compared
with PYTHIA Tune Z1. The plot shows the
average number of charged particles per
NSD collision per unit h, (1/NNSD) dN/dh.
 CMS NSD data on the charged particle rapidity
distribution at 7 TeV compared with PYTHIA
Tune Z1. The plot shows the average number of
charged particles per NSD collision per unit hf,
(1/NNSD) dN/dhdf.
“Minimum Bias” Collisions
Proton
Cracow School of Physics
Zakopane, June 13, 2011
4
Proton
Rick Field – Florida/CDF/CMS
Page 20
MB versus UE
Charged Particle Density: dN/dhdf
Transverse Charged Particle Density: dN/dhdf
2.5
RDF Preliminary
CMS Data
PYTHIA Tune Z1
PYTHIA Tune Z1
Charged Particle Density
Charged Particle Density
2.5
2.0
Factor of 2!
1.5
1.0
Charged Particles (|h| < 2, all pT)
0.5
Tune Z1
CMS
2.0
Tune Z1
NSD = ND + DD
1.5
1.0
0.5
7 TeV ND
pyZ1 ND = dashed
7 TeV
NSD (all pT)
pyZ1 NSD = solid
0.0
0.0
0
5
10
15
20
25
-4
-3
-2
-1
0
1
2
3
Pseudo-Rapidity h
PT max (GeV/c)
 Shows the density of charged particles in
the “transverse” region as a function of
PTmax for charged particles (All pT, |h| < 2)
at 7 TeV from PYTHIA Tune Z1.
Outgoing Parton
 CMS NSD data on the charged particle rapidity
distribution at 7 TeV compared with PYTHIA
Tune Z1. The plot shows the average number of
charged particles per NSD collision per unit hf,
(1/NNSD) dN/dhdf.
“Minimum Bias” Collisions
PT(hard)
Initial-State Radiation
Proton
Proton
Underlying Event
Outgoing Parton
Proton
Underlying Event
Proton
Final-State
Radiation
Cracow School of Physics
Zakopane, June 13, 2011
4
Rick Field – Florida/CDF/CMS
Page 21
MB versus UE
Charged Particle Density: dN/dhdf
"Transverse" Charged Particle Density: dN/dhdf
2.5
CMS Data
ATLAS
2.0
Charged Particle Density
"Transverse" Charged Density
2.5
Factor of 2!
1.5
RDF Preliminary
1.0
ATLAS corrected data
Tune Z1 generator level
0.5
7 TeV
Charged Particles (pT > 0.1 GeV/c, |h|<2.5)
CMS
PYTHIA Tune Z1
2.0
Tune Z1
1.0
0.5
pyZ1 ND = dashed
7 TeV
NSD (all pT)
0.0
NSD = ND + DD
1.5
pyZ1 NSD = solid
0.0
0
2
4
6
8
10
12
14
16
18
20
-4
-3
PTmax (GeV/c)
-2
-1
0
1
2
3
Pseudo-Rapidity h
 ATLAS data on the density of charged
particles in the “transverse” region as a
function of PTmax for charged particles (pT
> 0.1 GeV/c, |h| < 2.5) at 7 TeV compared
with PYTHIA Tune Z1.
Outgoing Parton
 CMS NSD data on the charged particle rapidity
distribution at 7 TeV compared with PYTHIA
Tune Z1. The plot shows the average number of
charged particles per NSD collision per unit hf,
(1/NNSD) dN/dhdf.
“Minimum Bias” Collisions
PT(hard)
Initial-State Radiation
Proton
Proton
Underlying Event
Outgoing Parton
Proton
Underlying Event
Proton
Final-State
Radiation
Cracow School of Physics
Zakopane, June 13, 2011
4
Rick Field – Florida/CDF/CMS
Page 22
Baryon & Strange Particle
Production at the LHC
 Strange Particle Production in Proton-Proton Collisions at 900 GeV with
ALICE at the LHC, arXiv:1012.3257 [hep-ex] December 18, 2010.
INEL
 Production of Pions, Kaons and Protons in pp Collisions at 900 GeV with
ALICE at the LHC, arXiv:1101.4110 [hep-ex] January 25, 2011.
 Strange Particle Production in pp Collisions at 900 GeV and 7 TeV, CMS
Paper: arXiv:1102.4282 [hep-ex] Feb 21, 2011, submitted to JHEP.
Step 1: Look at the overall particle yields (all pT).
-
K
K
Kshort
p
u s
u s
d s +d s
uud
+

 
ud s
dss
INEL
NSD
I know there are
more nice results
from the LHC, but
this is all I can show
today. Sorry!
Step 2: Look at the ratios of the overall particle yields (all pT).
Step 3: Look at the pT dependence of the particle yields and ratios.
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 23
Kaon Production
Kshort Rapidity Distribution: dN/dY
Kshort Rapidity Distribution: dN/dY
0.5
0.4
CMS
CMS Data
PYTHIA Tune Z1
0.4
CMS & ALICE Data
INEL = NSD + SD
PYTHIA Tune Z1
7 TeV
0.3
dN/dY
dN/dY
CMS NSD
0.3
0.2
900 GeV
900 GeV
0.2
0.1
0.1
ALICE INEL
Tune Z1
NSD (all pT)
0.0
pyZ1 NSD = solid
Tune Z1
pyZ1 INEL = dashed
0.0
-4
-3
-2
-1
0
1
2
3
4
-4
-3
Rapidity Y
-2
-1
0
1
2
3
4
Rapidity Y
 CMS NSD data on the Kshort rapidity
 CMS NSD data on the Kshort rapidity
distribution at 7 TeV and 900 GeV
distribution at 900 GeV and the ALICE point
compared with PYTHIA Tune Z1. The plot
at Y = 0 (INEL) compared with PYTHIA
shows the average number of Kshort per NSD
Tune Z1. The ALICE point is the average
collision per unit Y, (1/NNSD) dN/dY.
number of Kshort per INEL collision per unit Y
at Y = 0, (1/NINEL) dN/dY.
“Minimum Bias” Collisions
Proton shortage of Kaons in PYTHIA
No overall
Proton Tune Z1!
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 24
Kaon Production
Charged Kaons Rapidity: dN/dY
Rapidity Distribution Ratio: Kaons/Pions
Rapidity Distribution Ratio: Kshort/Kaons
0.3
0.8
0.6
ALICE Data
ALICE Data
ALICE
dN/dY
0.4
0.2
PYTHIA Tune Z1
ALICE Data
-
Kshort/(K++K-)
(K +K )
0.6
0.4
0.2
0.2
0.1
pyZ1 NSD = dashed
GeV
TuneINEL
Z1(all pT)
pyZ1 INEL900
= solid
900 GeV
INEL (all pT)
0.0
INEL (all pT)
-3
-2
-1
0
Tune Z1
900 GeV
0.0
0.0
-4
(K++K-)/(p++p-)
ALICE
PYTHIA Tune Z1
dN/dY Particle Ratio
dN/dY Particle Ratio
PYTHIA Tune Z1
+
-4 1
-3 2
-2 3
-1 4
Rapidity Y
0
-4
1
-3 2
Rapidity Y
 ALICE INEL data on the charged kaon
rapidity distribution at 900 GeV compared
with PYTHIA Tune Z1. The plot shows the
average number of charged kaons per INEL
collision per unit Y at Y = 0, (1/NINEL)
dN/dY.
-2 3
-1 4
0
1
2
3
Rapidity Y
 ALICE INEL data on the charged kaon to
charged pion rapidity ratio at 900 GeV
compared with PYTHIA Tune Z1.
“Minimum Bias” Collisions
Protonshortage of Kaons in PYTHIA
ProtonTune Z1!
No overall
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 25
4
Kaon Production
CMS measures (1/NNSD) dN/dY
Kshort Rapidity Distribution: dN/dY
0.5
CMS Data
PYTHIA Tune Z1
dN/dY
0.4
7 TeV
0.3
0.2
900 GeV
0.1
I have plotted the same data twice!
NSD (all pT)
This is the
correct way!
0.0
-4
-3
-2
-1
0
1
2
3
4
versus |Y| from 0 → 2
Rapidity Y
 Rick’s plot of the CMS NSD data on the Kshort
rapidity distribution at 7 TeV and 900 GeV.
The plot shows the average number of Kshort
per NSD collision per unit Y, (1/NNSD) dN/dY,
versus Y from -2 → 2.
 Real CMS NSD data on the Kshort rapidity
distribution at 7 TeV and 900 GeV. The plot
shows the average number of Kshort per NSD
collision per unit Y, (1/NNSD) dN/dY, versus
|Y| from 0 → 2.
Warning: I am not plotting what CMS actually measures!
I am old and I like to see both sides so I assumed symmetry about Y = 0 and plotted the same data on both
sides (Y → -Y). The way CMS does it is the correct way! But my way helps me see better what is going on.
Please refer to the CMS publication for the official plots!
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 26
Lambda Production
(Lam+LamBar) Rapidity Distribution: dN/dY
0.25
Rapidity Distribution Ratio: (Lam+LamBar)/(2Kshort)
0.5
_
CMS Data
(+)
7 TeV
PYTHIA Tune Z1
dN/dY Particle Ratio
dN/dY
0.20
0.15
0.10
900 GeV
0.05
CMS
NSD (all pT)
0.00
-4
-3
-2
-1
1
_
CMS
0.4
(+)/(2Kshort)
7 TeV
0.3
0.2
Factor of 1.5!
0.1
Tune Z1
NSD (all pT)
Tune Z1
0
CMS Data
PYTHIA Tune Z1
0.0
2
3
4
-4
-3
Rapidity Y
-2
-1
0
1
2
3
4
Rapidity Y
 CMS NSD data on the Lambda+AntiLambda  CMS NSD data on the Lambda+AntiLambda to
rapidity distribution at 7 TeV and 900 GeV
2Kshort rapidity ratio at 7 TeV compared with
compared with PYTHIA Tune Z1. The plot
PYTHIA Tune Z1.
shows the average number of particles per
NSD collision per unit Y, (1/NNSD) dN/dY.
“Minimum Bias” Collisions
Proton Tune Z1!
Oops!Proton
Not enough Lambda’s in PYTHIA
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 27
Cascade Production
Rapidity Distribution Ratio: (Cas+CasBar)/(2Kshort)
(Cas+CasBar) Rapidity Distribution: dN/dY
0.03
CMS Data

dN/dY Particle Ratio
7 TeV
dN/dY
0.02
CMS
900 GeV
0.01
PYTHIA Tune Z1
0.04
7 TeV
0.03
Factor of 2!
0.02
0.01
Tune Z1
NSD (all pT)
( + )/(2Kshort)
CMS
CMS Data

( + )
PYTHIA Tune Z1
_
0.05
_
Tune Z1
NSD (all pT)
0.00
0.00
-4
-3
-2
-1
0
1
2
3
4
-4
-3
-2
-1
0
1
2
3
4
Rapidity Y
Rapidity Y
 CMS NSD data on the Cascade-+AntiCascade-  CMS data on the Cascade-+AntiCascade- to
rapidity distribution at 7 TeV and 900 GeV
2Kshort rapidity ratio at 7 TeV compared with
compared with PYTHIA Tune Z1. The plot
PYTHIA Tune Z1.
shows the average number of particles per NSD
collision per unit Y, (1/NNSD) dN/dY.
“Minimum Bias” Collisions
Proton Tune Z1!
Yikes! Proton
Way too few Cascade’s in PYTHIA
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 28
PYTHIA Fragmentation
Parameters
Can we increase the overall rate of strange baryons by varying a few
fragmentation parameters?
Warning!
This may cause
problems
 PARJ(1) : (D = 0.10) is P(qq)/P(q),
the suppression
of diquark-antidiquark
pair production in
fitting the LEPproduction.
data. If so Notation: PARJ(1) = qq/q
the colour field, compared with quark–antiquark
we must understand why!
We
not want of
one
tune for
 PARJ(2) : (D = 0.30) is P(s)/P(u),
thedo
suppression
s quark
pair production in the field
+
e e and
another
one for
compared with u or d pair production.
Notation:
PARJ(2)
= s/u.
hadron-hadron collisions!
 PARJ(3) : (D = 0.4) is (P(us)/P(ud))/(P(s)/P(u)), the extra suppression of strange diquark
production compared with the normal suppression of strange quarks.
Notation: PARJ(3) = us/u .
This work is very preliminary!
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 29
PYTHIA Fragmentation
Parameters
Rapidity Distribution Ratio: (Lam+LamBar)/(2Kshort)
Rapidity Distribution Ratio: Kaons/Pions
0.5
0.3
dN/dY Particle Ratio
-
+
PYTHIA Tune Z1
us/s: 0.4 -> 1.0
0.1
Z1 default
qq/q: 0.1 -> 0.2
(+)/(2Kshort)
qq/q: 0.1 -> 0.2
0.4
0.3
0.2
us/s: 0.4 -> 1.0
0.1
Z1 default
s/u: 0.3 -> 0.5
7 TeV
NSD (all pT)
900 GeV
INEL (all pT)
_
CMS Data
-
(K +K )/(p +p )
s/u: 0.3 -> 0.5
PYTHIA Tune Z1
0.2
+
dN/dY Particle Ratio
ALICE Data
0.0
0.0
-4
-3
-2
-1
0
1
2
3
-4
4
-3
-2
-1
0
1
2
3
4
Rapidity Y
Rapidity Y
Rapidity Distribution Ratio: (Cas+CasBar)/(2Kshort)
0.05
_
( + )/(2Kshort)
CMS Data
dN/dY Particle Ratio
 PYTHIA Tune Z1C: Same as Tune Z1
except qq/q is increased 0.1 → 0.12 and
us/s is increased from 0.4 → 0.8.
PYTHIA Tune Z1
0.04
qq/q: 0.1 -> 0.2
us/s: 0.4 -> 1.0
0.03
0.02
s/u: 0.3 -> 0.5
0.01
NSD (all pT)
Z1 default
7 TeV
0.00
-4
-3
-2
-1
0
1
2
3
Rapidity Y
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 30
4
Kaon Production
Kshort Rapidity Distribution: dN/dY Rapidity Distribution Ratio: Kaons/Pions
Kshort Rapidity Distribution: dN/dY
0.5
0.2
Charged Particle Ratio
dN/dY Particle Ratio
0.3
CMS Data
ALICE Data
PYTHIA
7 TeV Tune Z1 & Z1C
PYTHIA Tune Z1
0.4
dN/dY
0.5
0.3
CMS Data
0.2
9000.1
GeV
0.1
CMS
NSD (all pT)
Tune Z1
INEL (all pT)
0.0
-4
-3
-2
-1
900 GeV
0
Rapidity Y
0.0
1
-4
2
-3
Tune Z1C
+
-
+
-
(K +K
)/(p
)
PYTHIA Tune Z1C
qq/q:
0.1+p
-> 0.12
0.4
7 TeV
us/s: 0.4 -> 0.8
0.3
Z1C
0.2
900 GeV
Z1
0.1Tune Z1C
CMS
qq/q: 0.1 -> 0.12
NSD (all pT)
us/s: 0.4 -> 0.8
Tune Z1C
0.0
3
-2
4
-1
-4
0
-3
1
Rapidity Y
-2
2
-1
3
0
4
1
2
3
Rapidity Y
 CMS dNSD ata on the Kshort rapidity
 CMS NSD data on the Kshort rapidity
distribution at 7 TeV and 900 GeV compared
distribution at 7 TeV and 900 GeV compared
with PYTHIA Tune Z1C. The plot shows the
with PYTHIA Tune Z1. The plot shows the
average number of Kshort per NSD collision
average number of Kshort per NSD collision per
per unit Y, (1/NNSD) dN/dY.
unit Y, (1/NNSD) dN/dY.
“Minimum Bias” Collisions
Proton
Proton
For Kaon production
Tune Z1 and Z1C are
almost identical!
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 31
4
Lambda Production
(Lam+LamBar) Rapidity Distribution: dN/dY
(Lam+LamBar) Rapidity Distribution:
dN/dYDistribution Ratio: (Lam+LamBar)/(2Kshort)
Rapidity
0.25
0.5
CMS Data
PYTHIA Tune Z1
0.10
0.05
0.00
-3
-2
-1
0.3
0.2
900 GeV
0.1
1-4
2-3
0.20
0.15
7 TeV
CMS
7 TeV
(+)
Z1C
0.10
Tune Z1C
qq/q: 0.1 -> 0.12
Z1
us/s: 0.4 -> 0.8
900 GeV
Tune Z1C
0.00
0.0
0
(+)/(2Kshort)
Tune0.05
Z1C
qq/q: 0.1 -> 0.12NSD (all pT)
us/s: 0.4 -> 0.8
TuneNSD
Z1(all pT)
CMS
NSD (all pT)
Charged Particle Ratio
dN/dY Particle Ratio
dN/dY
0.15
0.4
_
_
CMS Data
PYTHIA Tune Z1C
PYTHIA Tune Z1 & Z1C
0.20
-4
0.25
_
CMS Data
7 TeV
(+)
3-2
Rapidity Y
4-1
0 -4
1 -3
Rapidity Y
 CMS NSD data on the Lambda+AntiLambda
rapidity distribution at 7 TeV and 900 GeV
compared with PYTHIA Tune Z1. The plot
shows the average number of particles per
NSD collision per unit Y, (1/NNSD) dN/dY.
2 -2
3 -1
4 0
1
2
3
Rapidity Y
 CMS NSD data on the Lambda+AntiLambda
rapidity distribution at 7 TeV and 900 GeV
compared with PYTHIA Tune Z1. The plot
shows the average number of particles per
NSD collision per unit Y, (1/NNSD) dN/dY.
“Minimum Bias” Collisions
Proton more Lambda’s in PYTHIA
Proton
Not bad! Many
Tune Z1C!
Cracow School of Physics
Zakopane, June 13, 2011
4
Rick Field – Florida/CDF/CMS
Page 32
Cascade Production
(Cas+CasBar) Rapidity Distribution: dN/dY
(Cas+CasBar) Rapidity Distribution:
dN/dY
Rapidity
Ratio: (Cas+CasBar)/(Lam+LamBar)
Rapidity
Distribution
Ratio: (Cas+CasBar)/(2Kshort)
0.05
0.20
CMS Data
dN/dY
dN/dY Particle
Particle Ratio
Ratio
PYTHIA Tune Z1
dN/dY
0.02
CMS
0.01
0.00
-3
CMS Data
PYTHIA
Tune
& Z1C
Tune
Z1Z1
& Z1C
0.04 PYTHIA
7 TeV
0.15
0.03
0.10
0.02
900 GeV
0.05
0.01
-2
-1
0
0.00
1 -4
__
_
_
( + )
 +
 )/(2K
(
short)
PYTHIA Tune Z1C( + )/(+)
CMS
Data
CMS
Data
( + )
0.02
CMS
7 TeV
7 TeV
7 TeV
Z1C
Z1C
0.01
Z1
Tune
Z1C
Tune
Z1C
qq/q:
0.12
qq/q:
0.10.1
-> ->
0.12
NSD (all pT)
us/s:
0.4
->
us/s: 0.4 -> 0.80.8
NSD (all
(all pT)
pT)
Tune Z1 NSD
NSD (all pT)
-4
0.03
_
Charged Particle Ratio
0.03
Tune Z1C
qq/q: 0.1 -> 0.12
Z1
us/s: 0.4 -> 0.8
900 GeV
Tune Z1C
0.00
2 -3
3 -2
4 -1
Rapidity Y
0 -4
1 -3
Rapidity Y
 CMS NSD data on the Cascade-+AntiCascaderapidity distribution at 7 TeV and 900 GeV
compared with PYTHIA Tune Z1. The plot
shows the average number of particles per
NSD collision per unit Y, (1/NNSD) dN/dY.
2 -2
3 -1
4 0
1
2
3
Rapidity Y
 CMS NSD data on the Cascade-+AntiCascaderapidity distribution at 7 TeV and 900 GeV
compared with PYTHIA Tune Z1. The plot
shows the average number of particles per NSD
collision per unit Y, (1/NNSD) dN/dY.
“Minimum Bias” Collisions
Wow!Proton
PYTHIA Tune Z1C looks veryProton
nice here!
Cracow School of Physics
Zakopane, June 13, 2011
4
Rick Field – Florida/CDF/CMS
Page 33
Transverse Momentum
Distributions
PT Distribution: Kshort
PT Distribution: Lam+LamBar
1.0E+01
1.0E+00
CMS Data
CMS Data
1.0E-01
1.0E-02
Z1C
1.0E-03
1.0E-04
Tune Z1C
qq/q: 0.1 -> 0.12
us/s: 0.4 -> 0.8
NSD (|Y| < 2))
_
(+)
1.0E-02
Z1C
Z1
1.0E-03
1.0E-04
Tune Z1C
qq/q: 0.1 -> 0.12
us/s: 0.4 -> 0.8
NSD (|Y| < 2))
Z1
1.0E-05
7 TeV
PYTHIA Tune Z1 & Z1C
1.0E-01
dN/dPT (GeV/c)
dN/dPT (1/GeV/c)
7 TeV
PYTHIA Tune Z1 & Z1C
1.0E+00
1.0E-05
0
1
2
3
4
5
6
7
8
9
10
0
1
PT (GeV/c)
2
3
4
5
6
7
8
9
PT (GeV/c)
 CMS NSD data on the Kshort transverse
momentum distribution at 7 TeV compared
with PYTHIA Tune Z1 & Z1C. The plot
shows the average number of particles per
NSD collision per unit pT, (1/NNSD) dN/dpT
for |Y| < 2.
 CMS NSD data on the Lambda+AntiLambda
transverse momentum distribution at 7 TeV
compared with PYTHIA Tune Z1 & Z1C.
The plot shows the average number of
particles per NSD collision per unit pT,
(1/NNSD) dN/dpT for |Y| < 2.
“Minimum Bias” Collisions
Proton
PYTHIA Tune
Z1 & Z1C are a bit off on theProton
pT dependence!
Cracow School of Physics
Zakopane, June 13, 2011
10
Rick Field – Florida/CDF/CMS
Page 34
Transverse Momentum
Distributions
Cas+CasBar PT Distribution: dN/dPT
PT Distribution: Cas+CasBar
1.0E+00
1.0E-01
CMS Data
PYTHIA Tune Z1 & Z1C


( + )
Z1C
Z1
1.0E-03
NSD (|Y| < 2))
_


( + )
1.0E-02
7 TeV
PYTHIA Tune Z1 & Z1C
_
Probability
dN/dPT (1/GeV/c)
CMS Data
7 TeV
Z1C
1.0E-01
Z1
1.0E-02
Tune Z1C
qq/q: 0.1 -> 0.12
us/s: 0.4 -> 0.8
NSD (|Y| < 2))
Tune Z1C
qq/q: 0.1 -> 0.12
us/s: 0.4 -> 0.8
Normalized to 1
1.0E-03
1.0E-04
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
PT (GeV/c)
PT (GeV/c)
 CMS NSD data on the Cascade-+AntiCascade-  CMS NSD data on the Cascade-+AntiCascadetransverse momentum distribution at 7 TeV
transverse momentum distribution at 7 TeV
compared with PYTHIA Tune Z1 & Z1C. The
(normalized to 1) compared with PYTHIA
plot shows the average number of particles per
Tune Z1 & Z1C.
NSD collision per unit pT, (1/NNSD) dN/dpT for
|Y| < 2.
“Minimum Bias” Collisions
Proton
PYTHIA Tune
Z1 & Z1C are a bit off on theProton
pT dependence!
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 35
Particle Ratios versus PT
PT Particle Ratio: (Lam+LamBar)/(2Kshort)
0.8
Particle Ratio: (Lam+LamBar)/(2Kshort)
0.8
_
CMS Data
_
ALICE Data
(+)/(2Kshort)
PYTHIA Tune Z1 & Z1C
(+)/(2Kshort)
0.6
Z1C
Z1C
Ratio
PT Particle Ratio
PYTHIA Tune Z1 & Z1C
0.6
0.4
Tune Z1C
qq/q: 0.1 -> 0.12
us/s: 0.4 -> 0.8
0.2
Z1
NSD (|Y| < 2)
0.4
0.2
Tune Z1C
qq/q: 0.1 -> 0.12
us/s: 0.4 -> 0.8
900 GeV
7 TeV
INEL (|Y| < 0.75)
0.0
Z1
0.0
0
1
2
3
4
5
6
7
8
9
10
0
PT (GeV/c)
1
2
3
4
5
6
PT (GeV/c)
 CMS NSD data on the Lambda+AntiLambda  ALICE INEL data on the Lambda+AntiLambda
to 2Kshort ratio versus pT at 7 TeV (|Y| < 2)
to 2Kshort ratio versus pT at 900 GeV (|Y| < 0.75)
compared with PYTHIA Tune Z1 & Z1C.
compared with PYTHIA Tune Z1 & Z1C.
“Minimum Bias” Collisions
Tune Z1C Proton
is not too bad but a bit off on the
pT dependence!
Proton
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 36
Particle Ratios versus PT
PT Particle Ratio: (Cas+CasBar)/(Lam+LamBar)
PT Particle Ratio: (Cas+CasBar)/(2Kshort)
0.15
CMS Data

0.30
Z1C
0.05
NSD (|Y| < 2)
0.00
0
1
Tune Z1C
qq/q: 0.1 -> 0.12
us/s: 0.4 -> 0.8
7 TeV
2
3
4
_
( + )/(+)
PYTHIA Tune Z1 & Z1C
0.25
PT Particle Ratio
0.10
_
CMS Data

( + )/(2Kshort)
PYTHIA Tune Z1 & Z1C
PT Particle Ratio
_
Z1C
0.20
0.15
0.10
Z1
NSD (|Y| < 2)
Z1
Tune Z1C
qq/q: 0.1 -> 0.12
us/s: 0.4 -> 0.8
0.05
7 TeV
0.00
5
6
7
8
0
1
2
3
4
5
6
7
8
PT (GeV/c)
PT (GeV/c)
 CMS NSD data on the Cascade-+AntiCascade-  CMS NSD data on the Cascade-+AntiCascadeto Lambda+AntiLambda ratio versus pT at 7
to 2Kshort ratio versus pT at 7 TeV (|Y| < 2)
TeV (|Y| < 2) compared with PYTHIA Tune Z1
compared with PYTHIA Tune Z1 & Z1C.
& Z1C.
“Minimum Bias” Collisions
Proton
Tune Z1C
is not too bad but a bit off on Proton
the pT dependence!
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 37
Particle Ratios versus PT
PT Particle Ratio: Kaons/Pions
Rapidity Distribution Ratio: Kaons/Pions
0.60
0.3
ALICE Data
+
+
-
ALICE Data
(K +K )/(p +p )
PYTHIA Tune Z1 & Z1C
(K++K-)/(p++p-)
PYTHIA Tune Z1 & Z1C
0.40
dN/dY Particle Ratio
PT Particle Ratio
-
Z1C
Z1
0.20
Tune Z1C
qq/q: 0.1 -> 0.12
us/s: 0.4 -> 0.8
900 GeV
INEL (|Y| < 0.75)
0.2
Z1C
0.1
900 GeV
INEL (all pT)
0.00
Z1
Tune Z1C
qq/q: 0.1 -> 0.12
us/s: 0.4 -> 0.8
0.0
0
1
2
PT (GeV/c)
3
4
-4
-3
Tails of the pT distribution.
Way off due to the wrong pT!
 ALICE INEL data on the charged kaons to
charged pions ratio versus pT at 900 GeV (|Y| <
0.75) compared with PYTHIA Tune Z1 & Z1C.
-2
-1
0
1
2
3
Rapidity Y
 ALICE INEL data on the charged kaon to
charged pion rapidity ratio at 900 GeV
compared with PYTHIA Tune Z1.
“Minimum Bias” Collisions
Tune Z1C isProton
not too bad but a way off on the
pT dependence!
Proton
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 38
4
Particle Ratios versus PT
PT Particle Ratio: (P+Pbar)/Pions
Rapidity Distribution Ratio: (P+Pbar)/Pions
0.4
_
(p+p)/(p++p-)
ALICE Data
PYTHIA Tune Z1 & Z1C
_
(p+p)/(p++p-)
ALICE Data
PYTHIA Tune Z1 & Z1C
dN/dY Particle Ratio
PT Particle Ratio
0.12
0.3
Z1C
0.2
Z1
Tune Z1C
qq/q: 0.1 -> 0.12
us/s: 0.4 -> 0.8
0.1
900 GeV
INEL (|Y| < 0.75)
Z1C
0.09
0.06
Z1
0.03
900 GeV
INEL (all pT)
0.0
Tune Z1C
qq/q: 0.1 -> 0.12
us/s: 0.4 -> 0.8
0.00
0
1
2
PT (GeV/c)
3
4
-4
-3
Tails of the pT distribution.
Way off due to the wrong pT!
-2
-1
0
1
2
3
4
Rapidity Y
 ALICE INEL data on the Proton+AntiProton to  ALICE INEL data on the Proton+AntiProton
charged pions ratio versus pT at 900 GeV (|Y| <
to charged pion rapidity ratio at 900 GeV
0.75) compared with PYTHIA Tune Z1 & Z1C.
compared with PYTHIA Tune Z1 & Z1C.
“Minimum Bias” Collisions
Tune Z1CProton
is not too bad but way off on the
pT dependence!
Proton
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 39
MB versus UE
Charged Particle Density: dN/dhdf
Transverse Charged Particle Density: dN/dhdf
2.5
RDF Preliminary
CMS Data
PYTHIA Tune Z1
PYTHIA Tune Z1
Charged Particle Density
Charged Particle Density
2.5
2.0
Factor of 2!
1.5
1.0
Charged Particles (|h| < 2, all pT)
0.5
Tune Z1
CMS
2.0
Tune Z1
NSD = ND + DD
1.5
1.0
0.5
7 TeV ND
pyZ1 ND = dashed
7 TeV
NSD (all pT)
pyZ1 NSD = solid
0.0
0.0
0
5
10
15
20
25
-4
-3
-2
-1
0
1
2
3
Pseudo-Rapidity h
PT max (GeV/c)
 Shows the density of charged particles in
the “transverse” region as a function of
PTmax for charged particles (All pT, |h| < 2)
at 7 TeV from PYTHIA Tune Z1.
Outgoing Parton
 CMS NSD data on the charged particle rapidity
distribution at 7 TeV compared with PYTHIA
Tune Z1. The plot shows the average number of
charged particles per NSD collision per unit hf,
(1/NNSD) dN/dhdf.
“Minimum Bias” Collisions
PT(hard)
Initial-State Radiation
Proton
Proton
Underlying Event
Outgoing Parton
Proton
Underlying Event
Proton
Final-State
Radiation
Cracow School of Physics
Zakopane, June 13, 2011
4
Rick Field – Florida/CDF/CMS
Page 40
UE Particle Type
Log Scale!
Transverse Charged Particle Density: dN/dhdf
Transverse Particle Density: dN/dhdf
2.5
10.000
RDF Preliminary
PYTHIA Tune Z1
PYTHIA Tune Z1
2.0
Particle Density
Charged Particle Density
RDF Preliminary
1.5
1.0
Charged Particles (|h| < 2, all pT)
7 TeV ND
charged particles
(p++p-)
1.000
(K++K-)
_
(p+p
)
_
0.100
(+)
_
0.010
( + )
0.5
Tune Z1
7 TeV ND
(|h| < 2, all pT)
0.001
0.0
0
5
10
15
20
25
0
5
10
 Shows the density of charged particles in
the “transverse” region as a function of
PTmax for charged particles (All pT, |h| < 2)
at 7 TeV from PYTHIA Tune Z1.
Outgoing Parton
PT(hard)
PT(hard)
Initial-State Radiation
Initial-State Radiation
Proton
Outgoing Parton
Underlying Event
Proton
Proton
Underlying Event
Final-State
Radiation
Cracow School of Physics
Zakopane, June 13, 2011
25
 Shows the density of particles in the
“transverse” region as a function of PTmax
for charged particles (All pT, |h| < 2) at 7
TeV from PYTHIA Tune Z1.
Outgoing Parton
Underlying Event
20
PTmax (GeV/c)
PT max (GeV/c)
Proton
15
Outgoing Parton
Rick Field – Florida/CDF/CMS
Underlying Event
Final-State
Radiation
Page 41
MB versus UE
"Transverse" Particle Density: dN/dhdf
Charged Particle Density: dN/dhdf
0.15
0.15
RDF Preliminary
Charged Particle Density
Particle Density
RDF Preliminary
Kshort
PYTHIA Tune Z1
0.10
Factor of ~2!
0.05
Kshort (|h| < 2, all pT)
Tune Z1
Kshort
PYTHIA Tune Z1
0.10
0.05
Kshort (all pT)
Tune Z1
7 TeV ND
7 TeV ND
0.00
0.00
0
5
10
15
20
25
-4
-3
-2
-1
0
1
2
3
Pseudo-Rapidity h
PT max (GeV/c)
 Shows the density of Kshort particles in the
“transverse” region as a function of PTmax
for charged particles (All pT, |h| < 2) at 7
TeV from PYTHIA Tune Z1.
 Shows the Kshort pseudo-rapidity distribution (all
pT) at 7 TeV from PYTHIA Tune Z1. The plot
shows the average number of particles per ND
collision per unit hf, (1/NND) dN/dhdf.
Outgoing Parton
“Minimum Bias” Collisions
PT(hard)
Initial-State Radiation
Proton
Proton
Underlying Event
Outgoing Parton
Proton
Underlying Event
Proton
Final-State
Radiation
Cracow School of Physics
Zakopane, June 13, 2011
4
Rick Field – Florida/CDF/CMS
Page 42
MB versus UE
Charged Particle Density: dN/dhdf
"Transverse" Particle Density: dN/dhdf
0.12
0.12
_
(p+p)
RDF Preliminary
RDF Preliminary
Charged Particle Density
Particle Density
PYTHIA Tune Z1
0.08
Factor of ~2!
0.04
Tune Z1
_
PYTHIA Tune Z1
(p+p)
0.08
0.04
7 TeV ND (all pT)
Tune Z1
7 TeV ND (|h| < 2,all pT)
0.00
0.00
0
5
10
15
20
25
-4
-3
-2
-1
0
1
2
3
Pseudo-Rapidity h
PT max (GeV/c)
 Shows the density of P+antiP particles in the
“transverse” region as a function of PTmax
for charged particles (All pT, |h| < 2) at 7
TeV from PYTHIA Tune Z1.
 Shows the P+antiP pseudo-rapidity distribution
(all pT) at 7 TeV from PYTHIA Tune Z1. The plot
shows the average number of particles per ND
collision per unit hf, (1/NND) dN/dhdf.
Outgoing Parton
“Minimum Bias” Collisions
PT(hard)
Initial-State Radiation
Proton
Proton
Underlying Event
Outgoing Parton
Proton
Underlying Event
Proton
Final-State
Radiation
Cracow School of Physics
Zakopane, June 13, 2011
4
Rick Field – Florida/CDF/CMS
Page 43
MB versus UE
"Transverse" Particle Density: dN/dhdf
_
0.04
RDF Preliminary
0.04
(+)
RDF Preliminary
Charged Particle Density
PYTHIA Tune Z1
Particle Density
Charged Particle Density: dN/dhdf
0.03
Factor of ~2!
0.02
0.01
Tune Z1
PYTHIA Tune Z1
_
(+)
0.03
0.02
0.01
Tune Z1
7 TeV ND (|h| < 2,all pT)
7 TeV ND (all pT)
0.00
Coming soon! Measurements
from CMS,
-4
-3
-2
-1
0
1
2
3
4
15
20
25
ATLAS,
and
ALICE
on
the
strange
Pseudo-Rapidity h
PT max (GeV/c)
particles andbaryons
in the
 Shows the density of +anti particles in
Shows the +anti pseudo-rapidity distribution
the “transverse” region as a function of“underlying
(allevent”.
p ) at 7 TeV from PYTHIA Tune Z1. The plot
0.00
0
5
10
T
PTmax for charged particles (All pT, |h| < 2)
at 7 TeV from PYTHIA Tune Z1.
shows the average number of particles per ND
collision per unit hf, (1/NND) dN/dhdf.
Outgoing Parton
“Minimum Bias” Collisions
PT(hard)
Initial-State Radiation
Proton
Proton
Underlying Event
Outgoing Parton
Proton
Underlying Event
Proton
Final-State
Radiation
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 44
Fragmentation Summary
Not too hard to get the overall yields of
baryons and strange particles roughly right
at 900 GeV and 7 TeV. Tune Z1C does a
fairly good job with the overall particle
yields at 900 GeV and 7 TeV.
K+
Kshort

u s
d s +d s
ud s
K-
p
 
u s
uud
dss
Warning! The Tune Z1C fragmentation
PT Distributions: PYTHIA
does notmay
describe
parameters
cause correctly
problems the pT distributions
fitting
data.None
If so of the fragmentation
of heavy particles (MC softer
thanthe
theLEP
data).
must understand
why!
parameters I have looked atwe
changes
the pT distributions.
Hence, if one
We dop not
want
one
tune
for
looks at particle ratios at large
you
can
see
big
discrepancies between
T
+e- and another one for
e
data and MC (out in the tails of the distributions)! “Minimum Bias” Collisions
hadron-hadron collisions!
ATLAS Tuning Effort: Fragmentation Proton
flavor tuning at the one of the four stages.
Proton
Other Fragmentation Tuning: There is additional tuning involving jet
shapes, FSR, and ISR that I did not have time to include in this talk.
Cracow School of Physics
Zakopane, June 13, 2011
Rick Field – Florida/CDF/CMS
Page 45